Outlining the biggest dangers for humanity today, Hawking, 74, also lamented the population growth and said that people should be more careful.

“We are in danger of destroying ourself by our greed and stupidity,” Hawking replied to what he thought were the biggest dangers for the mankind.

“We have certainly not become less greedy or less stupid. Six years ago, I was warning about pollution and overcrowding, they have gotten worse since then,” Hawking told Larry King while reminiscing about an old interview with the US television and radio host.

Hawing said the population had grown by half a billion in six years with no end in sight.

“At this rate, it will be eleven billion by 2100. Air pollution has increased by 8 per cent over the past five years. More than 80 per cent of inhabitants of urban areas are exposed to unsafe levels of air pollution,” he said.

The Oxford-born theoretical physicist said pollution, which he felt was the biggest problem facing humanity, had still not been addressed.

“The increase in air pollution and the emission of increasing levels of carbon dioxide. Will we be too late to avoid dangerous levels of global warming?” ‘The Independent’ quoted him as saying.

When asked about the dangers of artificial intelligence (AI), Hawking also highlighted his concerns over the increasing use of technology in warfare.

“Governments seem to be engaged in an AI arms race, designing planes and weapons with intelligent technologies. The funding for projects directly beneficial to the human race, such as improved medical screening seems a somewhat lower priority,” Hawking said.

“I don’t think that advances in artificial technology will necessarily be benign. Once machines reach the critical stage of being able to evolve themselves, we cannot predict whether their goals will be the same as ours,” he said.

“Mankind is in danger of destroying ourselves by our greed and stupidity,” Hawking had said in his 2010 interview.

In a recent discussion held at the Starmus science conference in Tenerife in Spain, Hawking echoed similar sentiments and argued that the situation had in fact gotten worse.